Description

• Human milk is recognized as the optimal nutrition for infants by the American Academy of Pediatrics (AAP), the World Health Organization (WHO), the Surgeon General, and all major medical groups.
• Physiology
  • Breast milk production
    • Lactogenesis I: Milk production begins around 16 weeks prenatally.
    • Lactogenesis II: onset of copious milk secretion around 2 to 3 days after vaginal delivery; under hormonal control initiated by the expulsion of placenta and decrease in progesterone levels
    • Lactogenesis III: Mature milk production (maintenance) depends on autocrine (local) control. The amount of milk removed influences milk volume. If milk is not removed, a protein (feedback inhibitor of lactation) accumulates and inhibits prolactin release.
    • Prolactin is released from the anterior pituitary in response to nipple stimulation and triggers milk secretion into the lumen of breast alveoli.
    • Oxytocin is released from the posterior pituitary gland, causing ejection of milk into the breast ducts (milk ejection reflex).
    • Let-down can be triggered by physical stimulation of the breast or by mental stimulation such as hearing a baby cry.
  • Composition
    • Largely independent of maternal diet, except for fatty acids and water-soluble vitamins.
    • Colostrum contains high levels of secretory immunoglobulin A for immune protection. Lactoferrin stimulates meconium passage and promotes colonization with protective lactobacillus bifidus.
    • High whey-to-casein ratio
    • Milk changes within a feed and throughout the day. Hindmilk and milk at night contains higher fat and calories.

Epidemiology

Risk Factors

• Contraindications to breastfeeding:
  • Infant with classic galactosemia
  • Maternal conditions:
    • HIV (in industrialized countries)
    • Illicit drug use
    • Active, untreated tuberculosis
    • Herpes simplex virus lesions on breast
    • HTLV-I– or HTLV-II–positive
    • Exposure to radioactive material, while there is radioactivity in the milk
    • Use of some medications, such as cytotoxic drugs
• Infant conditions that may interfere with breastfeeding:
  • Prematurity
  • Low birth weight
  • Hypotonia
  • Cleft lip or palate
  • Ankyloglossia (tongue-tie)
• Maternal conditions that may interfere with breastfeeding:
  • History of breast surgery
  • Abnormal breast shape (glandular insufficiency)
  • Inverted nipples
  • Medications that inhibit lactation
  • Endocrine: infertility, hypothyroidism, polycystic ovary, retained placenta, Sheehan syndrome, obesity
• Common reasons cited for early termination of breastfeeding:
  • Perceived insufficient milk supply
  • Poor latch
  • Sore nipples
  • Returning to work or school